关键词: 岩溶地面塌陷; 盾构隧道; 地铁施工; 武汉长江一级阶地;

Abstract: Aiming at the risk of karst ground collapse in the first terrace of the Yangtze River, the mechanism of karst collapse and the measures to prevent collapse in subway tunnel construction were studied. By constructing the physical model of karst collapse under the typical stratigraphic structure of the first terrace of the Yangtze River, the karst collapse process of "seepage liquefaction-flow soil leakage" was reappeared completely, and the typical karst ground collapse mechanism was verified. It showed that the collapse slope angle of the collapsed hourglass is 40°. Based on the collapse characteristics of physical model, the karst treatment and anti-collapse scheme of "outside of the tunnel equipped with isolation pile, with curtain grouting under the pile, inside the tunnel covered with karst grouting" was designed and put forward. The effectiveness of this scheme was preliminarily verified by groundwater seepage simulation. The study can provide reference for the design and construction of subway shield tunnel under the same karst geological conditions.

Key words: karst ground collapse; shield tunnel; subway construction; first terrace of the Yangtze River;